Panel's Rejection of PSA Test Spurs Mixed Reaction From Experts
FRIDAY, Oct. 7 -- News that a key government advisory panel will give a thumbs-down next week to a controversial blood test for prostate cancer is garnering both praise and condemnation from experts.
A draft report due out early next week from the United States Preventive Services Task Force (USPSTF) will recommend that healthy men forego regular prostate-specific antigen (PSA) testing aimed at spotting prostate cancer, the The New York Times and other media outlets reported Friday.
The USPSTF is the same independent group of medical experts that caused a firestorm in late 2009 when they ruled against the use of annual mammographies for average-risk women in their 40s.
The PSA test has been similarly controversial, since its overall benefit in saving mens' lives has been challenged by a number of studies. Among the reasons the USPSTF cited in rejecting the PSA test is that the screen does not save lives and instead can result in unnecessary treatments that can leave men with discomfort, impotence and incontinence.
According to the Times, the task force focused on the results of five trials, the two largest done in Europe and in the United States. The European trial included 182,000 men. Over nine years of follow-up, it found no reduction in deaths due to prostate cancer among men of all ages in the study who were underwent PSA testing. But it did find some reduction in deaths among men aged 55 to 69 who got the blood test.
The American trial, involving almost 77,000 men followed for over a decade, also failed to show an overall reduction in deaths among all the men who were screened.
"Unfortunately, the evidence now shows that this test does not save men's lives," Dr. Virginia Moyer, a professor of pediatrics at Baylor College of Medicine and chairwoman of the task force, told the Times. "This test cannot tell the difference between cancers that will and will not affect a man during his natural lifetime. We need to find one that does."
But Dr. Anthony D'Amico, chief of radiation oncology at Brigham and Women's Hospital in Boston and a prostate cancer expert, said the task force's recommendation is misguided.
D'Amico noted that in the European study, screening reduced cancer deaths among these younger men by 44 percent. The U.S. study also showed a 44 percent reduction in cancer death among younger men, he added. "If they look at all the screening studies, they will find that the people who benefited most from screening were the youngest and presumably the healthiest," he noted.
"The panel has not really appreciated the entirety of the evidence," D'Amico said. "Considering all of the data, it appears that younger or healthier men benefit from PSA screening."
Right now, most men are advised to undergo regular PSA tests beginning at age 50. However, because most prostate cancers grow very slowly and may never prove fatal, the value of early treatment has come into question.
Of course, some prostate tumors are aggressive and can prove deadly. Most experts acknowledge that the real problem, right now, is that there's no reliable test to tell a patient which type of tumor he might have.
Dr. Otis W. Brawley, chief medical officer of the American Cancer Society, also cautioned that the task force's decision is not yet set in stone.
"It is important to keep in mind that under the new USPSTF process, the recommendation is not final until the conclusion of the public comment period and the USPSTFs review of those comments," he said.
According to Brawley, the cancer society pored over the existing body of evidence in 2009 and at that point it determined that it could not conclude whether or not PSA screening saves lives.
"We have long been concerned, and it has been very apparent for some years, that some supporters of prostate cancer screening have overstated, exaggerated and, in some cases, misled men about the evidence supporting its effectiveness," Brawley said. "We need balanced, truthful information to be made widely available to physicians and patients when making important health decisions. Sadly, that has not happened with this disease."
Brawley believes men must have an opportunity to make an informed decision with their health care provider about screening for prostate cancer after they receive information about the uncertainties, risks and potential benefits associated with testing for early prostate cancer detection.
"The ACS also strongly asserted that prostate cancer screening should not occur without an informed decision-making process," Brawley added.
D'Amico, who supports PSA testing, added that while over-treatment based on PSA test results has been a problem, much of that can be eliminated if the test is based on the most accurate PSA results. To make the test more accurate, men should stay away from sexual activity just prior to the test, bike riding, horseback riding and colonoscopy, he said. In addition, they should not have a PSA test if they have a bladder or prostate infection; and should wait at least a month after it has cleared up.
"Also, once a person is diagnosed it doesn't mean that they have to undergo treatment -- they can have a discussion with their physician about the significance of this cancer," D'Amico said. "Diagnosing allows one to have the opportunity to understand whether this is a cancer that requires treatment or not. But, putting your hands over your eyes saying, 'I don't want to know,' actually can lead to unnecessary death."
"I would still recommend an annual PSA, particularly for men who are healthy and under 65," D'Amico concluded.
Another expert, Dr. Lionel L. Banez, also supports continued use of the test. Banez, an assistant professor in the division of urologic surgery at Duke University Medical Center, said "the draft of the USPSTF review does provide evidence that PSA screening reduces prostate cancer mortality -- albeit not in as great a magnitude to be called optimal."
Prostate cancer remains the second most common cause of cancer death in men after lung cancer, Banez noted. "Thus, a slight reduction in mortality could still translate in a substantial absolute number of lives saved. Though it is clear that we still need to find a better test to improve early detection of significant disease and to curtail over-treatment, it is not advisable to discourage use of a currently existing test that is proven to save lives," he said.
For more on prostate cancer, visit the U.S. National Cancer Institute.
Posted: October 2011